"Me again... and I'm here to pick up where I left off", Little Simz states over a growling bassline on the opening bars of her new album, GREY Area. Amid the chest-thumping chaos of jazz flute and playground chants, on the bold first track "Offence", the UK rapper aligns herself with male auteurs including Picasso, Jay-Z, and Shakespeare. This bravado lays the stage for a project that, in its fullness, actually takes the listener to dark, vulnerable, and tender places. First, though: a reminder that Little Simz is at the peak of her powers.

The 24-year-old independent artist has been living in the midst of a whirlwind since dropping Stillness in Wonderland, her second full-length album (and 11th release in total), in December 2016. Lauded by the Guardian and Pitchfork, the album earned Simz – real name Simbi Ajikawo – two AIM and two MOBO award nominations in 2017. In the same year, she curated a day festival at the Roundhouse, and joined Damon Albarn's Gorillaz as the support act on their global Humanz tour.

Simz is no stranger to success. By the time she was 21, Kendrick Lamar had called her "one of the illest doing it right now", and she was the first independent UK artist to ever be listed on Forbes' 30 Under 30. But in 2017, she experienced some of the loneliness and pressure that can come with forging an international career entirely on your own – and it was from this darker, more personal space that her greatest project yet began to take shape.

2017 was a time of change for Simz. "It was just figuring out that transition, from being a young girl, to coming into myself as a woman," she explains. "Being 23 was such a pivotal age for me, in feeling like no one really prepped me for this shit. No one could have prepped me. But [it was] just not knowing how hard my 20s were going to be, and constantly feeling like I'm in a state of confusion."

That confusion had her questioning her DIY career – a path she wouldn't change, but a path that any independent artist will tell you is a brutal road to success. "I was questioning, how much do you really love this shit?" she says. "You haven't been able to spend time with your family in ages. Do you love it that much?" As she spent copious amounts of time alone in hotels and venues around the world, while her relationships with friends and family shifted around her, Simz slipped into a depression. "I was in a lonely place, a dark place. As much as I knew I had people there for me, I still didn't feel like anyone was there for me. I just didn't feel like anyone got it."

GREY Area started with an idea that sprang into Simz's mind when she was feeling low in a hotel room in Amsterdam. Reflecting on what she'd like to do once the Humanz tour was over, she immediately realised she wanted to go into the studio with Inflo, a British hip-hop producer she has known since they were both children, who now works with Michael Kiwanuka and The Kooks. She called him, and immediately after finishing her last show, flew out to LA for days of sessions that turned into days of therapeutic talking. "I had so much to talk about, and I got in [the studio] with the right person, and that allowed me to do that and not feel weird. It allowed me to be an artist, to be emotional and sensitive, and make mistakes, and cry. I just needed to get all of that out my system."

While previous albums have explored conceptual, surrealist landscapes, GREY Area is straight from Little Simz's life. The title itself "represents the time of my life when I felt like nothing was black and white, nothing was straightforward, everything was confusing." Inflo was the perfect collaborator for Simz as she poured her heart out on the mic. "I was working with someone that knows me, knows my heart, and is able to be brutally honest. I needed that – I was so stuck in my way of doing things."

That radical change in her process is audible on GREY Area, which was entirely produced by Inflo, and is perhaps Simz's most cohesive and inventive release sonically to date. The instrumentation brims with flutes, guitars, funky basslines, and palpitating strings. "I've always loved live music," says Simz. "I just haven't had the means to be able to make it happen. With this record, it was like finally, I'm able to get a string quartet, and get someone to drive from Sweden just to play flute. I trusted Flo's ear, and where he could see me evolving to. It felt like growth."

In the past, Simz would be meticulous about recording her pre-written verses, but in the studio this time she learned how to create more freely, or as she puts it, "I had to learn to be okay with failing, and just be okay with things not going the way I wanted them to go. This way, I went in, vocals sounding mad rough, things out of place, things out of time, and I just trusted that it would all come together. Nothing was premade. I didn't want to build a concept, I just wanted it to be streams of thoughts. Just me."

The record raises many huge, soul-searching questions, but for Simz, making the music was itself the answer that she needed. "Even with all the heartbreak and the pain that I experienced that year, making this album was... money couldn't buy that kind of therapy," she reflects. "I couldn't have healed any other way." Having come through her lowest point, and had the bravery to embrace her imperfections and her humanity, Simz has emerged on a high: GREY Area is a no-holds-barred, unflinchingly honest modern classic of UK rap.